linux-kernel - [PATCH 04/14] nohz: Use lockdep to assert IRQs are disabled/enabled

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Date:   Fri, 20 Oct 2017 02:56:01 +0200
From:   Frederic Weisbecker <frederic@...nel.org>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Frederic Weisbecker <frederic@...nel.org>,
        Tejun Heo <tj@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "David S . Miller" <davem@...emloft.net>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
        Ingo Molnar <mingo@...nel.org>
Subject: [PATCH 04/14] nohz: Use lockdep to assert IRQs are disabled/enabled

Use lockdep to check that IRQs are enabled or disabled as expected. This
way the sanity check only shows overhead when concurrency correctness
debug code is enabled.

Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
 kernel/time/tick-sched.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 7b258c5..e179336 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -199,7 +199,7 @@ static bool check_tick_dependency(atomic_t *dep)
 
 static bool can_stop_full_tick(int cpu, struct tick_sched *ts)
 {
-	WARN_ON_ONCE(!irqs_disabled());
+	lockdep_assert_irqs_disabled();
 
 	if (unlikely(!cpu_online(cpu)))
 		return false;
@@ -962,8 +962,7 @@ void tick_nohz_idle_enter(void)
 {
 	struct tick_sched *ts;
 
-	WARN_ON_ONCE(irqs_disabled());
-
+	lockdep_assert_irqs_enabled();
 	/*
 	 * Update the idle state in the scheduler domain hierarchy
 	 * when tick_nohz_stop_sched_tick() is called from the idle loop.
-- 
2.7.4